Overview of an Advanced Hypersonic Structural Concept Test ... · Overview of an Advanced Hypersonic Structural Concept Test ... – Hinders ability to validate analysis and modeling

October 30 - November 1, 2007 FAP Annual Meeting - Hypersonics Project 1

Overview of an Advanced Hypersonic Structural Concept Test Program

Craig A. Stephens, Larry D. Hudson, and Anthony PiazzaNASA Dryden Flight Research Center


Outline

• Hypersonics M&S Advanced Structural Concepts Development– C/SiC Ruddervator Subcomponent Test Article (RSTA)

• Background• Task Objectives• Test Plan• Current Status

• Hypersonics M&S Experimental Methods– Extreme Environment Sensors

• Instrumentation Needs• Sensors of Interest• Examples of ongoing efforts

• Conclusions


C/SiC Ruddervator Subcomponent Test ArticleBackground

• One of the key technology efforts during the X-37 program was the development and validation testing of hot-structure control surfaces

– Part of the risk mitigation effort was the parallel development of X-37 control surfaces using both carbon-carbon (C/C) and carbon-silicon carbide (C/SiC)

• Two separate design and manufacturing teams developed subcomponent test articles

– C/C Flaperon subcomponent (built and tested)– C/C Ruddervator subcomponent (built and tested)– C/SiC Flaperon subcomponent (built and tested)– C/SiC Ruddervator subcomponent (built but not tested)

• The X-37 program down selected to C/C and proceeded with the development and testing of both ruddervator and flaperon qualification units

– Flaperon thermally / mechanically tested at NASA Dryden– Ruddervator mechanically tested at Wright-Patterson, AFB

X-37 C/C Flaperon Qual Unit Near Peak Temp of 2500°FNASA Dryden, August 2005

X-37 Control Surface Development ProgramX-37 Control Surface

Development Program


C/SiC Ruddervator Subcomponent Test ArticleBackground (Continued)

• NASA proposed the C/SiC RSTA as a testbed to support ARMD research objectives and worked to formulate a multi-partner program

– Lockheed Martin (LM) is evaluating C/C and C/SiC control surface technology for hypersonic programs and expressed interest in collaborating

• The X-37 C/SiC RSTA provides an opportunity to– Apply both re-entry and trans-atmospheric derived

thermal / structural loads to a hot-structure – Evaluate the thermal / structural performance of a C/SiC

hot-structure control surface– Compare the thermal / structural performance of a

C/SiC and C/C hot-structure control surface– Provide a testbed to evaluate the performance of

advanced high-temperature instrumentation

X-37 C/SiC Ruddervator

Subcomponent Test Article

(RSTA)

X-37 C/SiC Ruddervator

Subcomponent Test Article

(RSTA)

Windward Surface

Leeward Surface(w/out access panels)


C/SiC Ruddervator Subcomponent Test ArticleTeam Roles and Responsibilities

• Overall task management and test requirements definition• Thermal, structural, and ground-vibration testing• Non-destructive evaluation• High-temperature instrumentation

NASA Dryden

• Acoustic, vibration, and modal testing• Thermal / acoustic testingNASA Langley

• C/SiC RSTA designer• Test requirements support (X-37 & LM loads)• RSTA thermal / structural / dynamic analysis

Materials Research & DesignWayne, PA

• C/SiC RSTA manufacturer• RSTA modifications and assembly• Non-destructive evaluation support

GE AviationCeramic Composite ProductsNewark, DE

• LM derived loads definition• Oversight of LM related testingPalmdale, CA


C/SiC Ruddervator Subcomponent Test ArticleTest Objectives

• Evaluate the thermal, structural, and dynamic performance of the C/SiC RSTA through the application of relevant hypersonic thermal, structural, acoustic and vibration loads

– Maintains and extends NASA’s core knowledge in testing hypersonic structures• Obtain unique data through the development of test techniques• Application and evaluation of unique high-temperature instrumentation• Multi-mission simulation

– Perform NDE throughout RSTA testing to identify defects and track potential damage propagation

• Pre- and post-test structural analysis to support test operations and development of test database

– Provides an extensive database for the evaluation of design and analysis methods for hypersonic structures

• Provides data to validate advanced analysis techniques– High-temperature vibration analysis– Using test data, non-linear material properties, and contact elements

at fasteners to determine force levels at interfaces and fastener stresses (linear versus non-linear analysis comparison)

IR Pulsed Thermography NDE


C/SiC Ruddervator Subcomponent Test ArticleTest Plan

• Evaluate RSTA performance under two different hypersonic flight conditions– X-37: Re-entry conditions

• Higher heating rates (i.e. higher surface temperatures) over shorter time periods• Mechanical loads over short time periods• Vibration / acoustic loads maximum at lift-off (i.e. low temperature conditions)

– LM: Trans-atmospheric conditions• Lower heating rates (i.e. lower surface temperatures) over longer time periods• Mechanical loads over repeated cycles• Combined thermal / acoustic loads of interest

• Developed a four-phase test program for the RSTA– Phase 1: Acoustic and vibration loads to X-37 load conditions– Phase 2: Thermal and thermal / structural loading to X-37 and LM load conditions– Phase 3: Room-temperature mechanical loading to X-37 and LM load conditions– Phase 4: Vibration and thermal / acoustic testing to LM load conditions


C/SiC Ruddervator Subcomponent Test ArticlePhase 1 Tests (NASA Langley, Completed)

• Objective:– Evaluate RSTA dynamic performance

under X-37 vibration and acoustic loads• Test Sequence:

– Modal survey • Free-free / fixed boundary condition

– Pre-acoustic sine sweep– Acoustic testing– Vibration testing

• Post-acoustic sine sweep• Random vibration testing• Post-random sine sweep

• Data Acquired– Accelerations– Strains

• Database Elements– Test requirements document and test plan– Instrumentation drawings and test data– Test correlation report

Acoustic Test SetupAt LaRC Reverb Chamber

RSTARSTA

SupportStructureSupportStructure

RSTARSTA

Test Fixture

Test Fixture

Z-Axis Sine-Sweep Z-Axis Sine-Sweep

Shaker TableShaker Table

Y-Axis Sine-Sweep Y-Axis Sine-Sweep

Vibration Test SetupAt LaRC


C/SiC Ruddervator Subcomponent Test ArticlePhase 2 Tests (NASA Dryden, In Progress)

• Objective:– Evaluate RSTA performance under X-37 re-entry

and LM thermal / mechanical load conditions

• Test Sequence:– Modal Survey (completed)

• Free-free boundary condition– Room-temperature ground vibration test (GVT)– Elevated-temperature GVT– X-37 thermal loading (3 cycles)– X-37 thermal / mechanical loading (3 cycles)– LM thermal / mechanical loading (3 cycles)– Elevated-temperature GVT

• Status:– Pre-test predictions

• LM thermal / mechanical test conditions (completed)• X-37 thermal / mechanical test conditions (in progress)

– High-temperature sensor installations (in progress)– Thermal test hardware design (completed)– Thermal test hardware fabrication (in progress)

C/SiC RSTAC/SiC RSTA

ShakerShaker

IR Thermography NDE of the RSTA

Thermography SystemThermography System

Free-Free Modal Survey

Transient RSTA Leeward Temps from Pre-Test Analysis of LM Trajectory

Phase 2 Test Setup

Sensor Integration


C/SiC Ruddervator Subcomponent Test Article Phase 3 & 4 Tests

• Phase 3 Objective: (NASA Dryden)– Evaluate RSTA performance under X-37 derived 100%

DLL loads• Test Sequence:

– Multi-cycle loading to 100% DLL condition• Reverse loading

• Data To Be Acquired– Deflections (control surface and freeplay)– Strains– Input and reaction loads

• Phase 4 Objective: (NASA Langley, TBD)– Evaluate RSTA performance under LM derived vibration

and thermal / acoustic loads• Test Sequence:

– Modal survey (free-free boundary condition)– Pre-acoustic sine sweep– Thermal / Acoustic testing– Vibration testing

• Post-acoustic sine sweep• Random vibration testing• Post-random sine sweep

• Data To Be Acquired– Temperatures– Accelerations– Strains

Phase 3 Test Setup

Thermal Acoustics Facilityat NASA LangleyThermal Acoustics Facilityat NASA Langley

TAFA Test ChamberTAFA Test Chamber

Phase 4 Test Facility


Extreme Environment Structural SensorsHigh-Temperature Instrumentation Needs

Foil Strain Gage

Weldable Strain Gage

Wire Wound Strain Gage

Silica Fiber-Optic Strain Sensor

2000

Sapphire Fiber-Optic Strain Sensor(in development)

30001000

Hypersonic StructuresStrain Measurement

Area of Need

Com

mer

cial

ly A

vaila

ble Strain Sensor Type

Difficulty of InstallationLowMediumHigh

Difficulty of UseLowMediumHigh

• Issues– Hypersonic structures are utilizing advanced materials that operate at temperatures that

exceed current ability to measure structural performance – Robust structural sensors that operate accurately and reliably in hypersonic environments

do not exist• Implications

– Hinders ability to validate analysis and modeling techniques– Hinders ability to optimize structural designs

Temperature (°F)


Extreme Environment Structural SensorsInstrumentation Attachment Needs

• Hypersonic structural test or flight articles are usually one-of-a-kind, expensive, and time consuming to manufacture

– Metallics– Metal matrix composites– Superalloys – High-temperature composites (i.e. C/C, C/SiC, SiC/SiC)

• Issues– Integrating structural sensors that do not compromise

structural integrity • Drilling holes, mechanical fastening, etc. are typically not

allowed)– Developing sensor attachment methods that provide

valid measurements for all environmental loading conditions without adversely affecting the substrate

• Thermal conditions• Mechanical loading• Vibration and acoustic loads• Exposure to chemically reacting flows


Extreme Environment Structural SensorsHigh-Temperature Structural Measurements of Interest

• Strain– Sapphire fiber-optic sensors– High-temperature Bragg Gratings

• Temperature• Heat Flux

– Calibration methods• Acceleration• Deformation

Sensors and Sensory Materials

Bonding / attachment method development throughout

structural component operating range

Current Efforts:– SOA structural sensor assessment to coordinate NASA, NRA and SBIR opportunities– Evaluate sensor / systems under laboratory, ground test, and flight test opportunities


Extreme Environment Structural SensorsExample of Strain Sensing Technology Progression

Weldable Capacitive

Weldable Resistive

1960-1970 1980-1990 >20001960-1970 1980-1990 >2000

Large thermal outputs and measurement uncertainties

Improved temperature-compensation using flame-sprayed resistive gages

X-33X-33NASP

Improved measurement accuracy applying silica and sapphire fiber-

optic technology

X-37

CEVCEV

Flame-Sprayed ResistiveFiber-Optic Strain Sensor


Extreme Environment Structural Sensors Examples of Strain and Temperature Sensors

ThermalSprayingThermalSpraying

Nextel overbraidCeramic cement

Gold-coated silica fiber (125 micron)

8.5mm

Rokide flame sprayPlasma spray (2 mils)

Fiber-Optic Strain Sensor Installation

Max use ≈ 1850°FMax use ≈ 1850°F

C/C

• Challenge– Advance strain sensing technology beyond 2000°F– Develop durable high-temperature fiber-optic sensors– Advance temperature sensing methods– Develop sensor attachment techniques suitable for

hypersonic environments (ground and flight testing)

Thermocouple InstallationThermocouple Installation

Ceramiccement

Ceramiccement

Plasma/Rokide thermal sprayed basecoatPresent Attachment ≈ 2500°FPresent Attachment ≈ 2500°F

C/SiC


Extreme Environmental SensorsExamples of Acceleration, Heat Flux, Network Sensors

• Accelerometers– COTS sensors– NASA GRC

NASA GRCHigh-Temperature SiC High-g sensor

(1000°F)

0.75 in.

COTSHigh-Temperature Accelerometer

(900°F)

0.625 in.

1.0 in.

• Heat Flux Sensors– Low profile– Rapid response

Heat Flux ArrayARMD ExCap NRA Effort

(Tao Systems and Virginia Tech)

• Distributed Bragg Grating System– Simultaneous measurements of strain,

temperature, and deformation– Increase operating temperature

Pressure LoadingFiberFiber

Thermal Loading

Heat gunHeat gun


Extreme Environmental SensorsValidation of Sensor Outputs and Attachment Methods

• Goal: Provide valid sensor data to structural analysts– Validate sensor output through characterization testing

• Compare sensor outputs to available standards– Validate and assess attachment techniques

Dilatometer(3000°F, inert / air)

Dilatometer(3000°F, inert / air)

High-temp FO sensors on C/C in sample holder

High-temp FO sensors on C/C in sample holder

Strain Sensor Validation System

ClampClamp

Load barLoad bar

Loading mandrelLoading mandrel

LVDTLVDT

Thermal Cycling Furnace

3000°F, inert / air 3000°F, inert / air

Typical Systems forSensor Validation Testing

Black-Body Furnace


Conclusions

• Hypersonics M&S is developing– Advanced structural concepts for hypersonic vehicle applications– Ground test techniques to obtain data that validates structural performance

and analysis techniques for design optimization– Sensor technology to acquire structural data subjected to hypersonic

conditions for analysis validation and design optimization– A knowledge base for the technical community

Thermal Spraying Fiber-Optic

Strain Sensors

Fiber-Optic Strain Sensors in Test

Documents

Overview of an Advanced Hypersonic Structural Concept Test ... · Overview of an Advanced Hypersonic Structural Concept Test ... – Hinders ability to validate analysis and modeling